1. Field of the Invention
The present invention relates to a liquid ejection recording head included in a liquid ejection recoding apparatus that ejects liquid, on a recording medium, and a method of manufacturing the same.
2. Description of the Related Art
Lower-cost recording apparatuses are demanded in the market for liquid ejection recording apparatuses. To provide a lower-cost recording apparatus, the promotion of cost reduction of a liquid ejection recording head is effective because the percentage of the recording head relative to the total cost is high. Japanese Patent Laid-Open No. 2002-19120 discloses such a liquid ejection recording head.
In the configuration of the liquid ejection recording head disclosed in Japanese Patent Laid-Open No. 2002-19120, substrates are connected to a wiring member through leads. Such connection portions are sealed with two kinds of sealing members. A typical liquid ejection recording head is sealed with two kinds of sealing member in this way. The sealing member that seals upper portions of electrode leads is provided in order to protect the connection portions from liquid or external force, for example, contact with a recording medium. The sealing member, therefore, has to have a predetermined hardness and thickness. A sealing member having a relatively high viscosity can be used.
Lower portions of the electrode leads have to be sealed in order to protect the electrode leads from liquid. If a high-viscosity sealing member is used, the sealing member is difficult to spread on the lower portions of the electrode leads. Consequently, it is difficult to seal the electrode leads with no gap. Accordingly, a sealing member having a relatively low viscosity is typically used to seal the lower portions of the electrode leads.
As described above, the related-art liquid ejection recording heads are sealed with the two kinds of sealing members having different viscosities.
As described above, however, further reduction in the cost of the liquid ejection recording head is demanded. As for sealing with the two kinds of sealing members in the related art, the number of steps of applying the sealing members is increased because the two kinds of sealing members are used. Disadvantageously, this sealing is expensive.
Therefore, sealing may be performed using a single sealing member in a liquid ejection recording head. In this case, a sealing member having a relatively high viscosity is required to protect electrode leads. Upon sealing the electrode leads using only the high-viscosity sealing member as described above, the following problems have been found.
Since the viscosity of the sealing member is high, the sealing member is difficult to spread on lower portions of the electrode leads through the spaces therebetween. It is therefore difficult to apply the sealing member with no gap. A gap may be formed. In a heating step for hardening the sealing member, this gap expands due to heat, thus causing a problem.
If the sealing member could be applied with no gap, it takes long time until the sealing member spreads on the electrode leads with no gap because the viscosity of the sealing member is high. It is not suitable in terms of manufacturing cost.